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Home >> Browse Vulnerability Assessment Database >> Ubuntu Local Security Checks >> USN179-1 : openssl weak default configuration

Vulnerability Assessment Details

USN179-1 : openssl weak default configuration

Vulnerability Assessment Summary
openssl weak default configuration

Detailed Explanation for this Vulnerability Assessment

Summary :

These remote packages are missing security patches :
- libssl-dev
- libssl0.9.7
- openssl

Description :

The current default algorithm for creating "message digests"
(electronic signatures) for certificates created by openssl is MD5.
However, this algorithm is not deemed secure any more, and some
practical attacks have been demonstrated which could permit a possible hacker
to forge certificates with a valid certification authority signature
even if he does not know the secret CA signing key.

Therefore all Ubuntu versions of openssl have now been changed to use
SHA-1 by default. This is a more appropriate default algorithm for
the majority of use cases
however, if you still want to use MD5 as
default, you can revert this change by changing the two instances of
"default_md = sha1" to "default_md = md5" in /etc/ssl/openssl.cnf.

A detailed explanation and further links can be found at

Solution :

Upgrade to :
- libssl-dev-0.9.7e-3ubuntu0.1 (Ubuntu 5.04)
- libssl0.9.7-0.9.7e-3ubuntu0.1 (Ubuntu 5.04)
- openssl-0.9.7e-3ubuntu0.1 (Ubuntu 5.04)

Network Security Threat Level: High

Networks Security ID:

Vulnerability Assessment Copyright: Ubuntu Security Notice (C) 2005 Canonical, Inc. / NASL script (C) 2005 Michel Arboi

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